This document provides information on induction and augmentation of labor. It discusses the definitions of labor, induction, and augmentation. It reviews trends showing rising rates of labor induction in the US. Common indications and contraindications for induction are outlined. Methods for evaluating maternal and fetal status prior to induction are described. Various pharmacologic and mechanical methods for cervical ripening are explained in detail. Finally, the document reviews protocols for labor induction and augmentation using oxytocin and associated risks and complications.

1. INDUCTION & AUGUMENTATION
OF LABOR
Afework A. (MD)
ARH,Gyn-obs
January ,2012

2. Introduction
Labor
- The process of uterine contractions leading to progressive
effacement and dilatation of the cervix and birth of the baby.
 Induction
- Iatrogenic stimulation of uterine contractions to accomplish
delivery prior to the onset of spontaneous labor , with or without
ruptured membrane.
 Augmentations
-Iatrogenic stimulation of spontaneous contractions that are
considered in adequate because of failure of progress of
dilation and descent.

3. Induction of Labor
one of the most commonly performed obstetrical
procedures ,
 Between 1990 and 2006, the frequency of labor induction
approximately doubled, rising from 9.5% to 22.5%,
the annual incidence of labor induction or augmentation in
the US almost doubled from 20 % in 1989 to 38% in 2002,
Induction is associated with increased complications as
compared to spontaneous labor.

4. Indications
Labor may be induced for either maternal or fetal
indications.
Induction of labor is undertaken when both of
the following criteria are met :
1.continuing the pregnancy is believed to be
associated with greater maternal or fetal risk
than intervention to deliver the pregnancy,
2.there is no contraindication to vaginal birth.

5. Indications cont…
The magnitude of risk is influenced by factors
such as :
-gestational age,
-presence/absence of fetal lung maturity,
- severity of the clinical condition, and
- cervical status

6. Indications cont…
Common INDICATIONS include
1. PROM
2. Severe preeclampsia, eclampsia
3. Post term
4. APH sec. to AP
5. Chorioamnionitis
6. IUFD (fetal demise)
7. Fetal compromise
-IUGR
-Isoimmunization
-oligohydraminos
-Non reassuring antepartem fetal test
-gross congenital anomalies

7. Indications cont…
8.Maternal medical conditions
-DM
-Renal disease
-Chronic pulmonary disease
9.Logistic factors
-Risk of rapid labor
-Distance from hospital
-Psychosocial indications
-Advanced cervical dilation

8. Contraindications
Absolute contraindications
1. Prior classic C/S or transfundal uterine surgery
2. Active genital herpes infection
3. Placenta previa(grade III , IV) or vasa previa
4. Umbilical cord prolapse
5. Transverse or oblique fetal lie
6. Absolute cephalopelvic disproportion (as in
women with pelvic deformities)

9. Contraindications cont…
Relative contraindications
1. Breech presentation
2. Cervical carcinoma
3. Multiple pregnancy
4. Prior LUST C/S
5. Grand multiparity
6. Fetal macrosomia

10. Evaluation before Labor Induction
PARAMETER CRITERA
MATERNAL
Confirm indication for induction
Review contraindications to labor and/or vaginal delivery
Perform clinical pelvimetry to assess pelvic shape and adequacy of
bony pelvis
Assess cervical condition (assign Bishop score)
Review risks, benefits and alternatives of induction of labor with
patient
FETAL/ NEONATAL
Confirm gestational age
Assess need to document fetal lung maturity status
Estimate fetal weight (either by clinical or ultrasound examination)
Determine fetal presentation and lie
Confirm fetal well-being

11. Evaluation cont…
 Criteria for Confirmation of Gestational Age and Fetal Pulmonary Maturity
I.Clinical criteria
1.≥39 weeks' gestation have elapsed since the first day of the LNMP in a
women with a regular menstrual cycle.
2.Fetal heart tones have been documented for ≥20 weeks' gestation by
nonelectronic fetoscope or for ≥30 weeks by Doppler ultrasound.
II.Laboratory determination
1.≥36 weeks' gestation have elapsed since a positive serum Hcg test.
2.Ultrasound estimation of GA is considered accurate if it is based on crown-
rump measurements obtained at 6 to 11 weeks' gestation or it is based on BPD
measurements obtained before 20 weeks' gestation.
III.Fetal pulmonary maturity
1. Lecithin/sphingomyelin (L/S) ratio >2:1
2. Presence of phosphatidylglycerol (PG)
3. TDxFLM assay ≥70 mg surfactant per 1 g albumin present
4. Presence of saturated phosphatidylcholine (SPC) ≥ 500 ng/mL in nondiabetic
patients (≥1000 ng/mL for pregestational diabetic patients)

12. Evaluation cont…
 CERVICAL Condition assessement
-The condition of the cervix or "favorability“ is important to
the success of labor induction
- One quantifiable method predictive of an outcome of
labor induction is that described by Bishop (1964).
- This system tabulates a score based upon the station of
the presenting part and four characteristics of the cervix:
1.dilatation
2. effacement
3.consistency, and
4. position

13. Modified Bishop scoring system
0 1 2 3
Dilation, cm Closed 1-2 3-4 >=5
Effacement, % 0-30 40-50 60-70 ≥80
Station* -3 -2 -1,0 +1,+2
Cervical
consistency
Firm Medium Soft
Position of the
cervix
Posterior Midposition Anterior

14. Evaluation cont…
If the Bishop score is high (≥8), the likelihood
of vaginal delivery is similar whether labor is
spontaneous or induced
The cervix is favorable when the score is > 6
and labor is usually successfully induced with
oxytocine
When score is < 5 cervix is unfavorable and
cervical ripening should be done

15. Methods of Cervical Ripening
I.PHARMACOLOGIC METHODS
1. PGE2 (dinoprostone)
2. PGE1 (misoprostol)
3.Mifepristone (progesterone receptor antagonist)
II. MECHANICAL METHODS
1.Membrane stripping (sweeping)
2.Amniotomy ( ARM)
3.Hygroscopic dilators (Laminaria)
4.Transcervical balloon catheters

16. 16
Dinoprostone ( PGE2)
PGE2 Gel (dinoprostone)
– Used widely for cervical ripening
– Causes dissolution of collagen bundles and increase in
sub mucosal water content
– PG induced cervical ripening often includes initiation of
labor.
– Low dose PG
• Increases chance of successful induction
• Decreases incidence of prolonged labor
• Reduces total and maximum oxytocine dose –

17. 17
• Preparation
– Interacervical (0.3 – 0.5mg)
– Interavaginal (3 – 5mg)
– Dinoprostone vaginal insert (cervidil) 10mg. provides
slower release 0.3mg/hr
 One advantage of the insert is it can be removed in case of
Hyper stimulation.

18. 18
• Administration
– Administer at or near labor ward
– The woman remains recumbent for at least 30 minutes
– Observe the patient from 30min to 2hrs
– Monitor FHB and contraction
– If no contraction transfer or discharge the patient .
– Discontinue PG and begin oxytocin infusion if
• Membranes rupture
• Cervical ripening has been achieved
• Labor has started
• Or 12 hours has passed

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• Side effects
– Hyper stimulation > 6 cont 10min
– Fever
– Vomiting
– Diarrhea
– Precaution should be taken when using it in
patients with
• Glaucoma
• B-Asthma
• Hepatic or renal failure

20. 20
Misoprostole (PGE1)
• Available as 100ug tab for prevention of peptic
ulcer
• Less expensive from dinoprostone
• Intera vaginal administration of 25ug not more
frequent than every 3-6hrs is effective in
women with unfavorable cervix

21. Membrane stripping
 Stripping the membranes mechanically dilates the cervix which
releases prostaglandins.
 The membranes are stripped by inserting the examining finger
through the internal os & moving it in a circular direction to detach
the inferior pole of the membranes from the lower uterine segment.
 Risks include :
- patient’s discomfort,
-infection,
- bleeding from undiagnosed placenta previa or low lying
placenta,and
-accidental ROM.

22. Amniotomy (ARM)
 Also referred as surgical induction
 Indications
• Induce labor
• Use of internal fetal monitoring
• Intra uterine assessment of uterine counteraction
 Risks
1- Prolapse of the umbilical cord (0.5%)
2- Chorioamnionitis: Risk increases with prolonged induction-
delivery interval
3- Postpartum hemorrhage: Risk is doubled compared with women
with spontaneous onset of labor
4- Rupture of vasa previa
5- Neonatal hyperbilirubinemia
6-Increase perinatal HIV transmission

23. Hygroscopic dilators
 absorb endocervical and local tissue fluids, causing the device to
expand within the endocervix and provide mechanical pressure.
 Can be either:
-natural osmotic dilators (e.g., Laminaria japonicum) or
-synthetic osmotic dilators (e.g., Lamicel).
 Advantages: 1- Outpatient placement
2- No need for fetal monitoring
 Risks: fetal and/or maternal infection

24. Balloon Catheters
 A fluid filled balloon is inserted inside the cervix.
 The Balloon provide mechanical pressure directly on the
cervix which respond by ripening and dilation.
 A Foley catheter (26 Fr) or specifically designed balloon
devices can be used
 Can be applied:
- With extra-amniotic saline infusion, or
- With concomitant oxytocin administration

25. Transcervical balloon catheter

26. 26
Labor induction and Augmentation
with Oxytocine
• Oxytocine is the first polypeptide hormone
synthesized
• FHB and contraction should be observed during
pitocine use.
• Variety of methods for stimulation of uterine
contraction with oxytocine has been used
• The goal is to achieve effective uterine contraction
that’s sufficient to produce cervical change and fetal
descent while avoiding uterine hyper stimulation and
/or non reassuring FHB

27. 27
• Contractions must be evaluated continuously
Discontinue pitocine
– if contractions are >5/10min or
>7/15min or
If they last longer than 60-90 seconds or if FHB becomes non
reassuring
 Uterine response occurs 3-5 minutes after beginning of
infusion of oxytocine – steady plasma level is achieved
40minuts later

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• Response depends on
– Previous uterine activity
– Uterine sensitivity
– Cervical status
• Different regimens are used for oxytocine
infusion .
– Low dose
– High dose

29. 29
Oxytocine Regimen for stimulation of labor
S/n Regiment Starting dose
(mu/min)
Incremental increase
mu/min
Dosage
interval
(min)
Max. dose
(mu/min)
1 Low dose 0.5-1 1 30-40 20
2 High dose 1-2 2 15 40
6 6,3,1 15-40 42

30. 30
WHO
oxytocine infusion rate for induction of labor )
Time since
induction
hrs
Oxytoinconc Drops/min Approx –
dose/miu/min
Vol infused Total vol
infused
0 2.5iu/500ml 10 3 0 0
½ Same 20 5 15 15
1 >> 30 8 30 45
1 ½ >> 40 10 45 90
2 >> 50 13 60 150
2 ½ >> 60 15 75 225
3 5Iu/500ml
(10miu/ml)
30 15 90 315
3 ½ >> 40 20 45 360
4 >> 50 25 60 420
4½ >> 60 30 75 495
5 10Iu/500ml
(20miu/ml)
30 30 90 585
5½ Same 40 40 45 630
6 >> 50 50 60 690
6½ >> 60 60 75 765
7 >> 60 60 90 855
N:B increase the rate of infusion until good contraction is established and maintain it at that rate

31. 31
Rapid escalation for primigranida only infusion rate for induction
of labor
Time since
induction hrs
Oxytoicn conc. Drops/min Approx –
dose/miu/min
0 2-5iu/500ml 15 4
½ >> 30 8
1 >> 45 11
1 ½ >> 60 15
2 5Iu/500ml
(10miu/ml)
30 15
2 ½ Same 45 23
3 >> 60 30
3 ½ 10Iu/500ml
(20miu/ml)
30 30
4 >> 45 45
4½ >> 60 60
5 >> 60 60

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Complications of induction of labor
1. Mother
– Failure of induction leading to c/s
– Uterine inertia
– Tetanic uterine contraction
– Uterine rupture
– Precipitated labor resulting in genital tear
– Intrauterine infection
– Post partum hemorrhage
– Water intoxication

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2. Fetus
– Prematurity
– Birth injuries
– Cord prolapse
– Fetal distress
– IUFD

34. THANK
YOU!